U2 guitarist The Edge has defended the size and cost of their 360 world tour, as the band rocked Wembley Stadium on the first night of their UK leg.

U2乐队吉他手The Edge为他们360世界之旅演唱会的规模和花费辩护，他们英国之旅第一晚震撼了温布利体育馆。

Each stage costs between £15m and £20m

Last month, protests delayed the removal of the custom-built set from Ireland, and it also came under fire from Talking Heads singer David Byrne.

The three steel structures cost between £15m and £20m each, offering a largely unobstructed view of the rock quartet（四重奏）.

The "claw" stage enabled an estimated 88,000 fans to watch U2 on Friday.

The huge green and orange structure in the centre of the stadium projected smoke and lights as the crowd looked on.

Before the concert, tour organisers claimed the crowd expected to attend would constitute the largest audience for a gig at Wembley Stadium.

Speaking to BBC 6 Music backstage, The Edge said: "We're spending the money on our fans, I don't think there's a better thing you could spend it on."

Despite it being the most ambitious（有雄心的，有抱负的） stage set of any band's world tour, topping the likes of Madonna and The Rolling Stones, Talking Heads frontman David Byrne was not impressed.

He slammed the band on his blog and said their world tour costs were "excessive", considering their stance（踏脚处，位置） on world hunger.

While on tour in Europe he wrote: "$40 million to build the stage and, having done the math, we estimate 200 semi trucks crisscrossing（交叉，十字形） Europe for the duration.

"It could be professional envy speaking here, but it sure looks like, well, overkill, and just a wee bit out of balance given all the starving people in Africa and all."

When asked whether the Irish rock veterans were stung by the criticism they received, The Edge told BBC 6 Music's Julie Cullen: "I think anybody that's touring is going to have a carbon footprint.

"I think it's probably unfair to single out rock 'n' roll. There's many other things that are in the same category but as it happens we have a programme to offset¹ whatever carbon footprint we have."

London tribute

When the tour reached Croke Park stadium in Ireland's capital last month, residents were angry at Dublin City's Council for giving roadies（巡回乐队管理员） permission to work through the night, with up to 100 trucks expected to drive through the narrow lanes around the venue².

"I think that's probably about as realistic as you can be right now," continued The Edge.

"We'd love to have some alternative to big trucks bringing the stuff around but there just isn't one."

U2 paid tribute to London as they played their massive gig on Friday night.

The capital, said Bono, was "a truly great city" that had been "very good" to the veteran foursome（四人的一组）.

"It's just occurred to me - we're older than Wembley Stadium," joked lead singer Bono near the beginning of U2's two-hour set.

The concert was the band's first at the venue since its reopening in 2007.

The Edge paid further tribute to his surroundings by producing a small snow globe at one point filled with miniature（小规模的，纤小的） London landmarks³.

Bono paid brief tribute to the late Joe Strummer, of London band The Clash, by singing a few bars from Rock the Casbah.

The singer signed off with a dedication⁴ to record producer Brian Eno, whom he hoped would "get well soon".

U2 return to Wembley later, where they will be supported by the Glasgow-based band Glasvegas.